Python activating environment variables

If you use *csh or fish, use activate.csh or activate.fish instead of activate:

falsetru@ubuntu:/tmp$ tcsh
ubuntu:/tmp> virtualenv aa
New python executable in aa/bin/python
Installing setuptools............done.
Installing pip...............done.
ubuntu:/tmp> source aa/bin/ac
activate          activate.csh      activate.fish     activate_this.py
ubuntu:/tmp> source aa/bin/activate      # <----------------
Badly placed ()'s.
ubuntu:/tmp> source aa/bin/activate.csh  # <----------------
[aa] ubuntu:/tmp>